Blue-black wool-dye and process of making same.



UNITED STATES PATENT Fries.

CARL OELSCHLAEGEL, OF BERLIN, GERMANY, ASSIGNOR TO THE AGTIEN-GESELLSCHAFT FUR ANILIN FABRIKATION, OF SAME PLACE.

BLUE-BLACK WOOL-DYE AND PROCESS oF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 628,025, dated July 4,1899-.

I Application filed April 8, 1899. Serial No. "112,305. (Speoimeiia) Toall whom it may concern.-

Be it known that I, CARL OELSOHLAEGEL, of Berlin, in the Kingdom ofPrussia, German Empire, have invented new and useful Improvements in theProduction of Bluish- Black Wool-Dyes; and I do hereby declare that thefollowing is a full, clear, and exact description of the invention,which will enable others skilled in the art to which it appertaius tomake and use the same.

My invention relates to the'production of a new black disazo dyestufffor W001 by means of a new sulfo-acid-namely, the sulfo-acid of paraamidophenyl beta naphthylamin, which possesses the followingconstitution so rr I have discovered that this acid may be used as firstcomponent in the production of disazo dyes by combining its diazocompound with one molecular proportion of alpha-naphthylamin,diazotizing again the resulting amidoazo compound and combining therediazotized product with beta -naphthol-beta -sulfoacid. The disazo dyeobtained in this way has been found to be a most Valuable product fordyeing Wool, producing on wool in an acidified bath bluish-black shadesof remarkable intensity and, moreover, fast to light and to milling.

The para-amidophenyl-beta i apht-hylaminsulfo acid used as startingproduct and which up to the present has not yet been described isprepared in the following manner: The sodium salt ofpara-nitrochlorbenzene-orthosulfoa'cid is dissolved in about ten tim esits weight of waterand heated in a closed vessel to about to centigradefor twelve hours, together with an equimolecular quantity ofbeta-naphthylamin and a suitable agent for the absorption of thehydrochloric acid formed during the reaction, such as sodium carbonate,calcium carbonate, &c. The reaction product obtained is directly reducedafter addition of hydrochloric acid by means tion the mass is renderedalkaline with car bonate of soda and filtered from theiron residues. Onaddition of common salt to the solution obtained the sodium salt ofpara-amidophenyl bet-a naphthylaminsulfo acid separates in crystallineform. It forms in dry state a grayish powder, readily soluble in hotwater, moderately soluble in cold water, and soluble. in alcohol. On theaddition of a mineral acid to the aqueous solution of this salt the freepara amidophenyl beta naphthylamin sulfo acid is precipitated.

For practically carrying out my invention I may proceed, for instance,as follows: 33.6 kilos of the sodiumsalt ofpara-amidophenyl-beta-naphthylaminsulfo acid are diazotized by means ofseven kilos of sodium nitrite and of thirty kilos hydrochloric acid, (22Baum.) The yellowish solution of the diazo compound obtained, from whicha portion of the latter is separated in form of a yellow crystallineprecipitate, is allowed to flowinto an aqueous solution of eighteenkilos of all pha-naphthylamin hydrochlorid. To the mixture thirty-fivekilos of sodium acetate are added, and the whole is stirred until thecombination is completed. The amidoazo compound formed in this wayrepresents a blueblack precipitate, which'after addition of a smallquantity of hydrochloric acid is filtered off and washed with coldwater. The amidoazo compound is then dissolved in Water on addition of'the necessary quantity of cans tic-soda lye. To this solution sevenkilos of 'sodiuninitrite dissolved in Water and thirty kilos ofhydrochloric acid (22 Baum) are added. The diazoazo compound formed inthis way is a blue-backprecipitate. It is introduced into a solution oftwenty-fivekilos of the sodium salt of beta -naphthol-beta monosulfoacid, which solution is kept alkaline by means of sodium carbonate. Themixture is well stirred during twenty hours. After gently heating, thedyestuff is isolated by addition of common salt, filtered off, pressed,

and dried. v

The dyestuff forms in dry state a brownblack powder which dissolvesreadily in water with blue color. On addition of causticsoda lye to thissolution a bluish-black preof iron, zinc, or the like. After thereduccipitation is formed. From the aqueous sothe above example withoutmaterially changing the character of the product obtained. Instead ofbeta -naphth0l-beta -sulfonic acid I may use beta -naphthol-beta-sulfonic acid or alpha -naphthol-alpha -sulfonic acid.

Having now described my invention, what I claim is l. The process forthe production of new disazo-dyestufi which consists in diazotizing thepara-amidophenyl-beta-naphthylaminsnlfoacid having the formula:

/ NH a l l l combining the diazo compound produced with one molecularproportion of alpha-naphthylamin, rediazotizing the amidoazo compoundthus obtained and. combining the diazoazo compound with anaphtholmonosulfo-acid, substantially as herein described.

2. The hereinbefore-described dye prepared by combining the 'diazocompound of paraamidophenyl-beta-naphthylamin -sulfo acid withalpha-naphthylamin, diazotizing again the intermediate product thusobtained and combiningitwith beta naphthol-beta -monosulfonic acid,which dye possesses in the form of its sodium salt the formula:

soaNa I a NaOfi I \W/N=N \N=N and forms when dry and pulverized abrownish-black powder, readily soluble in water,

giving a blue solution in which caustic-sodalye produces a bluish-blackprecipitate; the aqueous solution of the dye yielding on addition ofmineral acids aprecipitation of the free color-acid in the shape ofblue-black flakes; the dye being almost entirely insoluble in alcohol,dissolving in concentrated sulfuric acid with violet-black color whichby'ad'dition of ice-water turns at first to red-violet while on furtherdiluting a black precipitate is formed; said dye producingon wool in anacidified bath bluish-black shades.

In witness whereof I have hereunto signed my name, this 23d day ofMarch, 1899, in the presence of two subscribing witnesses.

CARL OELSCHLAEGEL.

